CAstDesignator* CParser::qualident(CAstScope *s)
{
//
// qualident ::= ident { "[" expression "]" }
//
CToken t;
// qualident -> ident ...
CAstDesignator *id = ident(s);
t = _scanner->Peek();
if (t.GetType() != tLBrak)
return id;
const CToken saveToken = id->GetToken();
const CSymbol* saveSymbol = id->GetSymbol();
CAstArrayDesignator *arrayId = new CAstArrayDesignator(saveToken, saveSymbol);
if (!arrayId->GetType() || !arrayId->GetType()->IsArray()) {
SetError(t, "access with index which is actually not an array");
return id;
}
free(id);
while (t.GetType() == tLBrak) {
// qualident -> ... "[" ...
Consume(tLBrak);
// qualident -> ... expression ...
arrayId->AddIndex(expression(s));
// qualident -> ... "]" ...
Consume(tRBrak);
t = _scanner->Peek();
}
arrayId->IndicesComplete();
return arrayId;
}
CAstStatAssign* CParser::assignment(CAstScope *s, CToken ident) {
//
// assignment ::= qualident ":=" expression.
// qualident ::= ident { "[" expression "]" }.
//
CToken t;
CAstDesignator *lhs = NULL;
CSymtab *symtab = s->GetSymbolTable();
if(_scanner->Peek().GetType() == tAssign) { // non-array case.
const CSymbol *tmpsym = symtab->FindSymbol(ident.GetValue(), sLocal);
if(tmpsym == NULL && symtab->FindSymbol(ident.GetValue(), sGlobal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(ident.GetValue(), sGlobal)) != NULL) {
SetError(ident, "designator expected.");
}
lhs = new CAstDesignator(ident, symtab->FindSymbol(ident.GetValue(), sGlobal));
}
else if(tmpsym != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(tmpsym) != NULL) {
SetError(ident, "designator expected.");
}
lhs = new CAstDesignator(ident, symtab->FindSymbol(ident.GetValue(), sLocal));
}
else
SetError(ident, "undefined identifier.");
assert(lhs != NULL);
}
else if(_scanner->Peek().GetType() == tLSBrak) { // array case.
const CSymbol *tmpsym = symtab->FindSymbol(ident.GetValue(), sLocal);
CAstArrayDesignator *arraylhs;
if(tmpsym == NULL && symtab->FindSymbol(ident.GetValue(), sGlobal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(ident.GetValue(), sGlobal)) != NULL) {
SetError(ident, "designator expected.");
}
arraylhs = new CAstArrayDesignator(ident, symtab->FindSymbol(ident.GetValue(), sGlobal));
}
else if(tmpsym != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(tmpsym) != NULL) {
SetError(ident, "designator expected.");
}
arraylhs = new CAstArrayDesignator(ident, symtab->FindSymbol(ident.GetValue(), sLocal));
}
else
SetError(ident, "undefined identifier.");
// multiple index.
while(_scanner->Peek().GetType() == tLSBrak) {
Consume(tLSBrak);
CAstExpression *expr = expression(s);
assert(expr != NULL);
arraylhs->AddIndex(expr);
Consume(tRSBrak);
}
arraylhs->IndicesComplete();
lhs = dynamic_cast<CAstDesignator *>(arraylhs);
assert(lhs != NULL);
}
CToken k;
Consume(tAssign, &k);
CAstExpression *rhs = expression(s);
assert(rhs != NULL);
return new CAstStatAssign(k, lhs, rhs);
}
CAstExpression* CParser::factor(CAstScope *s) {
//
// factor ::= qualident | number | boolean | char | string | "(" expression ")" | subroutineCall | "!" factor.
// FIRST(factor) = { tIdent, tNumber, tTrue, tFalse, tCharacter, tString, tLBrak, tEMark }.
//
CToken t;
EToken tt = _scanner->Peek().GetType();
CTypeManager *tm = CTypeManager::Get();
CAstExpression *n = NULL;
CSymtab *symtab = s->GetSymbolTable();
switch(tt) {
case tTrue:
Consume(tTrue, &t);
n = new CAstConstant(t, tm->GetBool(), 1);
break;
case tFalse:
Consume(tFalse, &t);
n = new CAstConstant(t, tm->GetBool(), 0);
break;
case tNumber:
{
Consume(tNumber, &t);
errno = 0;
long long v = strtoll(t.GetValue().c_str(), NULL, 10);
if (errno != 0) SetError(t, "invalid number.");
// integer range validation check.
if(v > 2147483648)
SetError(t, "integer constant outside valid range.");
n = new CAstConstant(t, tm->GetInt(), v);
break;
}
case tIdent:
{
Consume(tIdent, &t);
if(_scanner->Peek().GetType() == tLBrak) { // subroutineCall
Consume(tLBrak);
CAstFunctionCall *f;
// If subroutineCall calls undefined procedure/function, then set error.
if(symtab->FindSymbol(t.GetValue(),sLocal) == NULL && symtab->FindSymbol(t.GetValue(), sGlobal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sGlobal)) == NULL)
SetError(t, "invalid procedure/function identifier.");
f = new CAstFunctionCall(t, dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sGlobal)));
}
else if(symtab->FindSymbol(t.GetValue(), sLocal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sLocal)) == NULL)
SetError(t, "invalid procedure/function identifier.");
f = new CAstFunctionCall(t, dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sLocal)));
}
else
SetError(t, "undefined identifier.");
assert(f != NULL);
if(isExpr(_scanner->Peek())) {
CAstExpression *expr = expression(s);
assert(expr != NULL);
// If array, then addressed.
if(expr->GetType()->IsArray())
expr = new CAstSpecialOp(expr->GetToken(), opAddress, expr, NULL);
f->AddArg(expr);
while(_scanner->Peek().GetType() == tComma) {
Consume(tComma);
expr = expression(s);
assert(expr != NULL);
// If array, then addressed.
if(expr->GetType()->IsArray())
expr = new CAstSpecialOp(expr->GetToken(), opAddress, expr, NULL);
f->AddArg(expr);
}
}
Consume(tRBrak);
n = f;
}
else { // qualident
if(_scanner->Peek().GetType() == tLSBrak) { // It means array
CAstArrayDesignator *f;
if(symtab->FindSymbol(t.GetValue(), sLocal) == NULL && symtab->FindSymbol(t.GetValue(), sGlobal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sGlobal)) != NULL)
SetError(t, "designator expected.");
f = new CAstArrayDesignator(t, symtab->FindSymbol(t.GetValue(), sGlobal));
}
else if(symtab->FindSymbol(t.GetValue(), sLocal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sLocal)) != NULL)
SetError(t, "designator expected");
f = new CAstArrayDesignator(t, symtab->FindSymbol(t.GetValue(), sLocal));
}
else {
SetError(t, "undefined identifier.");
}
while(_scanner->Peek().GetType() == tLSBrak) {
Consume(tLSBrak);
CAstExpression *expr = expression(s);
assert(expr != NULL);
f->AddIndex(expr);
Consume(tRSBrak);
}
f->IndicesComplete();
n = f;
} // non-array case.
else {
if(symtab->FindSymbol(t.GetValue(), sLocal) == NULL && symtab->FindSymbol(t.GetValue(), sGlobal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sGlobal)) != NULL) {
SetError(t, "designator expected.");
}
n = new CAstDesignator(t, symtab->FindSymbol(t.GetValue(), sGlobal));
}
else if(symtab->FindSymbol(t.GetValue(), sLocal) != NULL) {
// Check if symbol is procedure.
if(dynamic_cast<const CSymProc *>(symtab->FindSymbol(t.GetValue(), sLocal)) != NULL) {
SetError(t, "designator expected.");
}
n = new CAstDesignator(t, symtab->FindSymbol(t.GetValue(), sLocal));
}
else
SetError(t, "undefined identifier.");
}
}
break;
}
case tString:
Consume(tString, &t);
n = new CAstStringConstant(t, t.GetValue(), s);
break;
case tCharacter:
{
Consume(tCharacter, &t);
char res;
// If character length is 0, it means character is '\0' because invalid character cases are handled in scanner.
if(t.GetValue().length() == 0)
res = '\0';
else if(t.GetValue().length() == 1) {
if(t.GetValue().at(0) != '\\')
res = t.GetValue().at(0);
else SetError(t, "wrong character");
}
// unescape.
else if(t.GetValue().length() == 2) {
if(t.GetValue().at(0) == '\\') {
if(t.GetValue().at(1) == 'n') {
res = '\n';
}
else if(t.GetValue().at(1) == 't') {
res = '\t';
}
else if(t.GetValue().at(1) == '"') {
res = '"';
}
else if(t.GetValue().at(1) == '\'') {
res = '\'';
}
else if(t.GetValue().at(1) == '\\') {
res = '\\';
}
else if(t.GetValue().at(1) == '0') {
res = '\0';
}
else
SetError(t, "wrong character");
}
}
else SetError(t, "wrong character");
n = new CAstConstant(t, tm->GetChar(), (long long)res);
break;
}
case tLBrak:
Consume(tLBrak);
n = expression(s);
Consume(tRBrak);
break;
case tEMark:
Consume(tEMark, &t);
n = new CAstUnaryOp(t, opNot, factor(s));
break;
default:
// cout << "got " << _scanner->Peek() << endl;
SetError(_scanner->Peek(), "factor expected.");
break;
}
return n;
}
